(NBC) — Wednesday night brings the season finales of all three of NBC’s “Chicago” dramas.

Possibly the most anticipated one is “Chicago Fire,” where wedding bells are set to ring for one on-screen couple, plus a fan-favorite character makes a return.

After giving new meaning to the phrase “burning love” last season with a proposal surrounded by flames and inching things along with an engagement ring this season, characters Stella Kidd and Kelly Severide, played by Miranda Rae Mayo and Taylor Kinney, are finally ready for a “Chicago Fire” wedding.

“It’s possible this could be the greatest season finale we’ve ever had,” said Mayo. “It definitely will be the fanciest, I think.”

But short notice nuptials require a little good fortune.

“I think the fans will be happy with the wedding and the outcome and hopefully, hopefully, nothing explodes, I dunno,” said Kinney.

In this case, the episode promises viewers an explosion of emotions and a Firehouse 51 reunion with actor Jesse Spencer returning as Matthew Casey to serve as Severide’s best man.

 “I don’t have to be in any bunker gear, I don’t have to go into a fire, get to wear a suit,” said Spencer about his guest appearance.

When asked what was it like having Spencer back on set, Kinney said it was like “second nature.”

“It was like a breath of fresh air having him walk onto set,” said Mayo of Spencer’s visit. “We all rushed him.”

And while Casey’s return goes as planned in the episode, not everything does.

“It’s still good luck to have rain on your wedding day, right?” said Spencer.

“Chicago Fire” fans will find out.

The “Chicago Fire” season finale airs Wednesday at 9 p.m. with the finales for “Chicago Med” at 8 p.m. and “Chicago PD” at 10 p.m.